Multiple Sclerosis Overview
About Multiple Sclerosis
Multiple sclerosis (MS) is a chronic, often disabling disease that attacks the central nervous system (CNS), which
is made up of the brain, spinal cord and optic nerves. Symptoms may be mild or severe, ranging from numbness
in the limbs to paralysis or loss of vision. The progression, severity and specific symptoms of MS are
unpredictable and vary from one person to another. Some people are minimally affected by the disease, while
others experience rapid progression to total disability.
According to the U.S. National Multiple Sclerosis Society, MS is thought to affect more than 2.1 million people
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worldwide. Best current estimates indicate that there are at least 400,000 people with MS in the United States.
While the disease is not contagious or directly inherited, factors associated with MS have been identified and
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include:
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Gender: MS is two to three times more common in women than men, indicating that hormones may
influence susceptibility to MS.
Genetics: Although MS is not directly hereditary, studies suggest that genetic factors play an important
role in determining who develops this disease.
Age: Most people are diagnosed with MS between the ages of 20 and 50, although onset may be earlier
or later.
Geography: The incidence of MS increases in countries further from the equator.
MS symptoms result when a person’s immune system attacks the myelin sheath, the protective insulation
surrounding nerve fibers in the CNS. The damage to the myelin sheath, and to the nerve fibers themselves,
interferes with the transmission of nerve signals between the brain and spinal cord, as well as other parts of the
body. When the myelin is destroyed, it is replaced by scars of hardened “sclerotic” tissue. As a result, some
underlying nerve fibers are permanently severed. This produces common symptoms of MS, which include pain,
fatigue, numbness, vision problems, cognitive dysfunction, as well as walking, balance and coordination
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problems.
Diagnosis and Treatment
At this time, there are no specific symptoms, physical findings or laboratory tests that can confirm that a person
has MS. Physicians use several strategies to determine if a person meets the long-established criteria for a
diagnosis of MS and to rule out other possible causes of the symptoms. These strategies include a careful
analysis of medical history, a neurological exam and various tests, including magnetic resonance imaging (MRI),
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evoked potential (EP) and spinal fluid analysis.
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In order to make a diagnosis of MS, the physician must:
 Find evidence of damage in at least two separate areas of the CNS
 Find evidence that the damage occurred on at least two separate occasions at least one month apart
 Rule out all other possible diagnoses
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MS has been divided into four disease courses:
There are four disease courses that people with MS typically experience, each of which can range from being
mild to severe in nature.
 Relapsing-Remitting MS (RRMS): The most common form of the disease, RRMS is characterized by
clearly defined acute attacks with full recovery or with residual deficit upon recovery. Periods between
disease relapses are characterized by a lack of disease progression, and the disease may be inactive for
months or years. Approximately 85 percent of people with MS are initially diagnosed with RRMS. Most
approved disease-modifying therapies are indicated for RRMS.
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Secondary-Progressive MS (SPMS): SPMS begins with an initial relapsing-remitting disease course,
followed by the development of progressive disability that often includes more relapses and no definitive
periods of remission.
Primary-Progressive MS (PPMS): PPMS is characterized by a slow onset and steadily worsening of
symptoms, and is not associated with distinct attacks like RRMS and SPMS. Instead, there is an
accumulation of deficits and disabilities which may level off or continue for months and years. Only 10
percent of MS patients have PPMS.
Progressive-Relapsing MS (PRMS): The least common disease course, occurring in approximately five
percent of all MS patients, PRMS shows a steady neurological decline from the beginning but with clear
acute relapses. There may or may not be some form of recovery following these relapses, but the disease
continues to progress without remissions.
There is currently no known cure for MS. There are approved disease-modifying medications that have been
shown to treat to treat exacerbations (e.g., damage to the myelin sheath) or manage the symptoms of MS. In
addition, there are many investigational treatments and technological advances in development to potentially help
people manage symptoms.
i
National Multiple Sclerosis Society (NMSS). FAQs about MS. Date accessed: Mar 11, 2013.
http://www.nationalmssociety.org/about-multiple-sclerosis/what-we-know-about-ms/faqs-about-ms/index.aspx
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NMSS. MS Prevalence. Date Accessed: March 11, 2013. http://www.nationalmssociety.org/about-the-society/msprevalence/index.aspx
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NMSS. Epidemiology of MS. Date accessed: Mar 14, 2013. http://www.nationalmssociety.org/about-multiple-sclerosis/whatwe-know-about-ms/who-gets-ms/epidemiology-of-ms/index.aspx
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NMSS. What we know about MS: Symptoms. Date accessed: Mar 14, 2013. http://www.nationalmssociety.org/aboutmultiple-sclerosis/what-we-know-about-ms/symptoms/index.aspx
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NMSS. Diagnosing MS. Date accessed: Mar 14, 2013 http://www.nationalmssociety.org/about-multiple-sclerosis/what-weknow-about-ms/diagnosing-ms/index.aspx
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NMSS. What is Multiple Sclerosis? Date Accessed: Mar 14, 2013. http://www.nationalmssociety.org/about-multiplesclerosis/what-we-know-about-ms/what-is-ms/index.aspx
FOR MEDIA ONLY
Biogen Idec 133 Boston Post Road Weston, MA 02493 Phone 781-464-2000 www.biogenidec.com